Measures against heat are required for electronic components that control an in-vehicle apparatus mounted on a vehicle, a different electronic component disposed in the same housing, and so forth in order to avoid a reduction in performance due to a temperature rise. A method of radiating heat generated by an electronic component via a substrate on which the electronic component is mounted is generally known as the measures against heat for the electronic components. In the case where the amount of heat radiated from the electronic component is large, however, the size of the substrate must be increased in order to improve the heat radiation performance.
Thus, Patent Document 1 proposes a technique of radiating heat generated by an electronic component to a housing made of metal by bringing the electronic component into contact with the housing via an adhesive in order to reduce the size of the substrate while enhancing the heat radiation performance for the electronic component.